Vitest

What it does

This skill equips AI agents with the ability to run Vitest, a fast and lightweight unit testing framework designed for modern JavaScript and TypeScript projects. It enables automated verification of code logic through snapshot testing, mocking dependencies, and parallel test execution within development environments.

When to use it

• Validate new feature implementations immediately after writing code to catch regressions early.
• Generate comprehensive test suites for complex TypeScript applications requiring type safety checks.
• Execute parallelized test runs to significantly reduce feedback loops during continuous integration pipelines.
• Mock external services or heavy dependencies to isolate unit logic from environmental variables.

Key capabilities

• Runs Vitest commands directly within the agent's execution context.
• Supports snapshot testing for verifying UI output and data structures.
• Enables dependency mocking for isolated unit test scenarios.
• Facilitates parallel test execution for faster feedback cycles.
• Integrates with standard JavaScript and TypeScript project configurations.

Example prompts

• "Run all Vitest tests in my current project directory and summarize any failures."
• "Generate a new snapshot test for the calculateTotal function using Vitest."
• "Execute unit tests while mocking the fetchUser API call to ensure isolated logic validation."

Tips & gotchas

Ensure your project has vitest installed as a dev dependency before attempting to run tests. Be aware that parallel execution may require specific configuration flags if your test suite relies on shared state or file system locks.